When Jethro brings their hound, Duke, in to the kitchen it's clear the dog is staring at its trainer as it has its back turned to Jed and Jethro.
When the Clampetts visit their neighbors, Jed rings the doorbell. However, in the previous and next episodes, the Clampetts have no idea what a doorbell is as they are confused with the "music" ringing through their house.